The present invention relates generally to structure and manufacture of modular bridges, and more particularly to modular bridge structures comprising fiber reinforced plastic (FRP) composite.
Conventional pedestrian bridges have typically been fabricated of steel, concrete, and wood. Some composite bridge structures have been proposed but use truss designs in which pultruded composite members are linked together so that each member takes compression or tension similarly to comparable steel construction. Certain composite vehicular bridge structures utilize non-winding fabrication techniques, each structure consisting of many individual parts all adhered or fastened together, which is very labor intensive during the fabrication phase. One such structure requires that truss-built sides be transported to the site and connected with composite members that comprise the floor deck. The bridge is built on site using standard assembly techniques, which may be satisfactory for standard building materials, but is marginal for composites. Because the structures can be fabricated only in part at a factory and must be assembled at the bridge site, substantial disruption of traffic flow may result. Assembly techniques for the structures use mechanical fasteners which create points of stress concentration.
The invention described herein solves or substantially reduces in critical importance problems with previously existing bridge structures and fabrication methods by providing an enclosed FRP composite bridge structure that exploits the high specific strength and stiffness of FRP materials, has low fabrication costs, omits nonstructural wall and roof members that add unnecessary weight, has a minimum number of mechanical fasteners and fewer sites for structural failure, is fabricated in modules with various cross sectional configurations, can be factory fabricated and assembled, thereby avoiding site weather conditions that hamper installation or compromise tolerances, and can be transported to the site completely assembled or in modules and installed with minimal disruption of traffic flow.
It is therefore a principal object of the invention to provide an FRP bridge structure and fabrication method.
It is a further object of the invention to provide an inexpensive, strong, lightweight and corrosion resistant bridge structure.
It is yet another object of the invention to provide an FRP bridge structure that can be fabricated in modular form and assembled to a desired length.
It is another object of the invention to provide a factory fabricated and assembled bridge structure for installation at a bridge site with minimal interruption of traffic flow.
It is yet another object of the invention to provide a bridge structure requiring substantially lower maintenance during bridge lifetime as compared to previously existing bridge structures.
These and other objects of the invention will become apparent as a detailed description of representative embodiments proceeds.